Sunlight–derived vitamin D affects interleukin-4 level, T helper 2 serum cytokines, in patients with Graves’ disease: a prospective cohort study
Abstract: Graves’ disease (GD)
is the most common autoimmune disease leading to hyperthyroidism. The role of
Th1/Th2 pathways balance in GD is still controversial. Vitamin D is reported to
have an effect on those pathways. This study aims to examine the effect of
sunlight exposure on vitamin D 25(OH) level and Th1 and Th2 pathway-derived
cytokines in GD patients.
Methods: A prospective cohort study was conducted on 32 GD patients to
compare the effect of sunlight exposure on vitamin D level and cytokines of Th1
and Th2 pathways between exposed and unexposed groups. Exposed group received
sunlight exposure three times a week for 30 minutes each between 9–11 a.m for 1
month. Thyroid stimulating hormone (TSH), free thyroxin (fT4), vitamin D
25(OH), interferon-γ (IFN-γ) and interleukin-4 (IL-4) serum levels, were
investigated before and after one month of sunlight exposure. Paired t-test or
Mann Whitney test were used to analyze the difference between exposed and unexposed
GD groups before and after sun exposure.
Results: One month of sunlight exposure increased vitamin D 25(OH) level
by 27.90% among exposed GD group (15.34 ng/mL to 19.62 ng/mL, p<0.001).
Meanwhile, unexposed GD group’s vitamin D 25(OH) level decreased from 20.48
ng/mL to 18.86 ng/mL (p<0.001). Increased vitamin D 25(OH) level in exposed
group was not accompanied by the increase of IL-4 level after sunlight
exposure.
Conclusion: Sunlight exposure increases vitamin D 25(OH) serum level and
may affect the level of IL-4, Th2 pathway-derived cytokine, in patients with
GD. However, the role of sunlight-derived vitamin D on IFN-γ in GD patients can
not be concluded in this study.
Author: Dyah Purnamasari,
Pradana Soewondo, Samsuridjal Djauzi
Journal Code: jpkedokterangg150335
